Embodiments of the inventive concept described herein relate to technologies of estimating channels in multiple-input multiple-output (MIMO) systems, and more particularly, relate to a channel estimation method for enhancing estimation accuracy for uplink channel estimation using a temporal correlation in MIMO systems which perform one-bit quantization.
A future communication system is expected to use a millimeter wave band to employ a very large wideband on the basis of a massive MIMO system with a transceiver in which a plurality of antennas are installed. When a base station (BS) knows the entire channel information, using large-scale antennas in the BS may reduce inter-user interference by simple linear processing and increase reliability by the channel hardening effect.
Massive MIMO may suffer from high implementation cost and power consumption by using a large number of radio frequency (RF) chains. It is possible to resolve these issues by using one-bit analog-to-digital converters (ADCs) or low-resolution ADCs since the ADC power consumption exponentially increases with its resolution level. Thus, the massive MIMO system using low-resolution ADCs or one-bit ADCs may greatly decrease in implementation cost and total power consumption.
Successful symbol detection, however, requires accurate channel state information at the BS. Because low-resolution ADCs heavily quantize received signals, the channel estimation becomes an extremely difficult task. There has been some recent work to tackle this problem. A near maximum likelihood channel estimator based on convex optimization was proposed, and a joint channel and data estimator were developed. Furthermore, to reduce the channel estimation complexity, the generalized approximate message passing algorithm was exploited, while the hybrid architectures was considered for channel estimation.
All the previous work, however, has not considered the temporal correlation, which is inherent in all communication channels.
Thus, one embodiment of the inventive concept proposes a new channel estimation technique which exploits the temporal correlation of channels in the massive MIMO system exploiting one-bit ADCs.